Perforator for tapes with punches controlled through electromagnets



June 1952 v. SVIDERCOSCHI 3,040,610

PERFORATOR FOR TAPES WITH PUNCHES CONTROLLED THROUGH ELECTROMAGNETS 2 Sheets-Sheet 1 Filed June 22, 1959 INVENTO R:

VII/girlie? SvzlciefcOsc/ul ailm ATTORNEBS June 26, 1962 v. SVIDERCOSCHI 3,040,610

PERFORATOR FOR TAPES WITH PUNCHES CONTROLLED THROUGH ELECTROMAGNETS Filed June 22, 1959 2 Sheets-Sheet 2 t INVENTOIL:

Virginia SVL'clercoSc/d ATTo {LNESS United States Patent Ofiice 3,640,619 Patented June 26, 1962 3,040,610 PERFORATGR FOR TAPES WITH PUNCHES CONTROLLED THROUGH ELEC'I'ROMAGNETS Virginia Svidercoschi, Milan, Italy, assignor to Saul.

Cogera Compagnia Generale Rappresentanze, Milan,

Italy, a company of Italy Filed June 22, 1959, Ser. No. 821,961 Claims priority, application Italy June 23, 1958 2 Claims. (Cl. 83-513) It is known that, with perforators for tapes of common kind, the power necessary for perforation is supplied to the punches by a motor which through linkages displaces said punches to make the holes; the displacement of each punch is carried out as a consequence of the energizing of the electromagnets which with their armature in working position transmit the movement of the linkages, pushed by the motor, to the respective punches.

That means that the punching of every perforation depends on the movement of two different units. clear that there must exist a close relationship between the two movements, and that their sequence must be accurately determined: this entails a considerable complication of construction and control, above all if it is desired to attain a high mrforating speed.

In order to meet the two fundamental requirements, namely the simplicity of construction and the high perforating speed, it has been suggested to provide a perforator for tapes equipped with electromagnets, each of which is adapted to perforate the tape by means of displacement of a punch directly connected to its own armature.

However the requirement of a high working speed prevented the use of an electromagnet similar to those employed at present with telephone selectors.

According to the present invention an electromagnet is provided wherein the means for the return of the armature after perforation are not constituted by a spring but by a force which is exerted upon said armature, while the latter is displaced to perform the perforation, whereby the force does not hinder to an appreciable extent the rapid displacement of said armature. As will be better explained in the following description, said return force is such as to be initially, during the displacement of the armature in the sense that operates the perforation, not only smaller than the force causing said displacement, but also decreasing with a certain rapidity, while said force causing the displacement that brings about the perforation proceeds to grow rapidly.

The perforator for tapes according to the invention, therefore, is characterized in that it comprises a series of electromagnets, each of which performs the perforation with a punch directly connected to its own armature, the return being obtained by electromagnetic means which preferably start action towards the end of the working stroke of said armature, exerting thereupon a decreasing force of attraction.

An example of embodiment of a perforator according to the invention will be described hereinafter, with refer ence to the accompanying diagrammatical drawing, wherein:

FIG. 1 shows an assembly view of the perforator; FIG. 2 shows the device for the transport of the tape; FIG. 3 is a detail view showing the attachment of a punch to the armature of the correspondinng electromagnet; FIG. 4 represents a variant of the energizing circuit for one of the electromagnets, and FIG. 5 is a graph relative to a possible embodiment of an electromagnetic device for controlling a punch.

It is In the example of FIGURE 1 there is indicated diagrammatically a perforator equipped with eight punches which serve for the perforation of service signals, and with a ninth perforator which perforates the so-called dragging track. The perforator comprises essentially a perforating matrix 1 with a slot 2 within which there comes to slide the tape 3 to be perforated (see vFIG. 2). Each punch 4, as will be described hereinafter, is connected directly to the armature of one of the electromagnetic device, generically indicated by 5. -In the drawing there are represented only some of those electro magnetic devices and the following explanation relates to any one thereof, all the other being completely identical in structure as Well as in operation.

Each electromagnetic device 5 comprises a core 6 of soft iron in the shape of an E on the extreme extensions 7 and 9 whereof there are placed two coils 10 and 11.

On the central extension 8 of said core 6 there is hinged an armature 12 with two arms 13, 14, which is connected, through the arm 13, to a punch 4 adapted to make a row of perforations in the tape 3. FIGURE 3 indicates diagrammatically the attachment of said punch 4 to said armature 12; it shows that the punch 4 is accommodated in a slot of the armature.

A small shaped plate indicated by 15 is fixed to the arm 13 of the armature 12 and retains the punch 4 by means of a slot through which an extension 4a of said punch passes. v

The working coil 10 which causes the perforation is connected to a source of current through a contact 16. On closing said contact 16, an electric current of adequate intensity passes through the coil 10.

A force is generated thereby which acts upon the arm 13 of the mobile armature, thereby compelling said armature to turn around its fulcrum in such a way that said arm 13 approaches the core of said coil 10. An insulating plate 17 is carried by the arm 13 thereby preventing a direct contact between the arm 13 and the core of the coil. On rotation of said armature, at a certain time the end of its arm 14 permits the closure of a con tact 19 which sends the current of the source to the coil 11 so that this second coil becomes energized and there is exerted a corresponding magnetic return force upon the arm 14 of the armature 12.

The coil 11 has such characteristics of structure and feed that upon the arm 14 there is exerted said force for returning the anchor, namely, a force tending to oppose the rotation previously started, however this force is such as not to hinder seriously said rotation which causes the arm 13 to approach the core of the coil 10.

It should be noted here that while said rotation continues, the force acting upon the arm 13 increases rapidly while that acting upon the arm 14 diminishes also rapidly, this latter arm moving away from the core of the coil 11. Consequently said armature, towards the end of its own rotation, possesses a high speed and, therefore, the punch 4, carrying outfthe perforation, comes to possess, at the time of said perforation, a considerable kinetic energy.

If, however, when the perforation has been terminated, the contact 16 is re-opened, the force generated by the coil 11 returns said armature to its rest position; in performing said return movement, the end of the arm 14 causes again the opening of the contact 19, and thereby interrupts the energization of the coil 11. The arm 14 of the armature 12 rests in its rest position on the core of the coil 11 through an insulating plate 18 similar to the plate 17 on the arm 13 but thinner.

In parallel to the contact 19 there is provided a condenser 20 which besides acting as an arcing contact, prolongs the energization of the coil 11 thereby ensuring the return of the armature 12 to rest position.

The invention also provides an embodiment adapted to moderate considerably the braking action of the coil 11. Said braking action in fact becomes substantial when the intensity of the current in the coil 11 has attained the stationary value, a certain length of time after the closing of the contact 19. Said length of time is greater than the so-called time constant of the coil 11 and increases with the increase of said time constant.

To prevent the closing of the contact 19 from exerting a substantial-braking action upon the anchor 12 the coil 11 can be dimensioned in such a way that its time constant T is substantially greater than the time interval between the closing of the contact 19 and the arrival of the armature 12 at the end of stroke under the action of the coil 10.

In the graph of FIG. there'is indicated the course of the intensity I of the current in the coil 11 as a function of time I. By 1,, is indicated the time that elapses between the closing of the contact 19 and the arrival of the armature, under the action of the coil 10, at the end of stroke; by I is indicated the intensity of the current in the coil 11 at the time at which the armature 12 arrives at the end of stroke. In the case of FIGURE 5 one gets; T =51 that is, the time constant T of the coil is five times the time t From the course of the current as a function of time one realizes instantly that the .value I attained by the current in the coil 11 at the end of the active stroke of the armature, is in that case really negligible if one considers moreover that the gap at the coil is a maximum at that time.

A cording to a possible different embodiment, of considerable importance, the coil 11 is energized permanently by a weak current, through a resistor 21 according to the diagram indicated in FIGURE 4.

Said. current will have to be adjusted in such a way as to be able tn retain safely the armature in rest position, preventing any possible recoils of said armature.

However said 'rest...current has a very small value becau se the respective magnetic circuit possesses a particularly lqw reluctance since the insulating plate 18 inserted between the arm 14 of the armature l2 and the core of the oi .1, i My The force due to this weak rest current not only ensures a stabile rest position of the armature 12, but also prevents the latter from moving until the flux generated by the coil by effect of the closing of the contact 16 has attained a predetermined value; as will 'be better explained hereinafter, that appears to be of particular interest.

In fact, in the case in which the coil 11 is not passed through by the rest current, if the coil 10 is energized,

the armature 12 starts its movement soon, being attracted by the coil 10 and, therefore, there very soon occurs the so-called anchor efiect, owing to which the current diminishes in the coil 10. As a consequence the punch 4 controlled by the anchor 12 strikes against the paper tape 3 to be perforated with an energy which may be insuificient for perforation: at that time, when the armature stops, the anchor effect ceases and, therefore, the intensity of the current in the coil 10 begins to rise again, whence after some instants the perforation is finally performed, So at least part of the kinetic energy stored by the armature and by the punch is wasted.

If instead the coil 11 is constantly passed through by a rest current, if the coil 10 is energized said rest current prevents at the beginning the rotation of the armature 12. While the armature remains at a standstill, the anchor efiect is lacking, so that the current in the coil 18 can increase in intensity.

At a certain time, the intensity of said current in the coil 10 comes to be such as to cause the rotation of the armature 12 thereby overcoming the opposition of the coil 11 due to the rest current: on starting said rotation, the anchor effect occurs, it is true, but, since the current in the coil 10 is by now suificiently high, the punch 4 arrives at the paper tape 3 with an energy suflicient to perform the perforation. It should be noted that in the present case (with rest current in the coil 11) the whole energy of the punch 4 becomes available to perform the perforation of the paper while in the case in which there is no rest current in the coil 11, the punch 4 comes to stop upon contact with said paper, losing inpractice its energy and it has, therefore, to perform the perforation by starting again from standstill.

From what has been set forth hereinbefore it appears that while it' is at any rate possible to obtain the perforation also without the rest current in the coil 11, by employing for the purpose a certain time, said perforation is obtained in a much shorter time in the case in which in the coil 11 there is said rest current. This is of considerable advantage in view of the work required to be done by perforators.

In FIG. 2 there is diagrammatically represented the electromagnetic device for the transport of the tape In said figure there are represented two rolls 22 and 23 between which there is dragged the tape 3, a toothed wheel coaxial and rigid with the roll 22, a thrust pawl 25 which is hinged at the armature 26 of the dragging magnet 27 and is adapted to mesh between the teeth of the wheel 24, while a stop 28, rigid with the support of the magnet 27 is adapted to limit the stroke of the pawl 25; a spring 29 serves to prevent the opposed rotations of the roll 22.

When the coil 30 of the magnet 27 attracts the annature 26 towards it, the pawl 25 causes the roll 22 to perform a partial revolution. As a consequence thereof, the latter, in cooperation with the roll 23 pressing towards the roll 22, determines a displacement of the tape 3 gripped between the two rolls.

In its rotation a second arm of said anchor 26 moves to close the contact 32 and, therefore, to energize the coil 31 of the electromagnet 27 whereby, if the coil 30 is deenergized, the coil 31 returns the armature 26 to its rest position; during said return the spring 29 keeps the roll 22 fixed. The operation and the electric connection of'the electromagnet 27 correspond to those of the electromagnets described with reference to FIG. 1.

While the adoption of an electromagnet 27 of the type described is advantageous thanks to its simplicity and quickness in operation, the forwarding of the tape 3 to be perforated might be controlled with any other known means.

It is possible to realize, according to the present invention, also electromagnetic devices for accomplishing the perforations, wherein the return of the armature connected to the punch 4, takes place through the same rest current which constantly passes through the coil 11 (FIG. 4), namely without the other current which in the examples described hereinbefore, starts action on the closing of the contact 19.

I claim:

1. A perforator for tapes, said perforator comprising a plurality of punches having tape-perforating ends, a separate electromagnetic device for each punch, each electromagnetic device comprising acore having a central portion and two opposed extensions, an armature swingably mounted upon said central portion and having two opposed arms extending adjacent said extensions, a separate coil upon each extension, means operatively connecting an end of one of said arms to a separate punch, a contact connected with an end of one of said coils, another contact connected with an end of the other one of said coils, means conductively connecting other ends of said coils to a terminal of a source of electrical energy, means conductively connecting said contacts to another terminal of the source of electrical energy and pennasaid one coil.

aently maintaining a weak current in said other coil, an 2. A perforator in accordance with claim 1, wherein insulating plate carried by said one arm and adapted to the third-mentioned means comprise a resistor connected engage said one coil when said one arm is attracted by to said other terminal and to said other contact. said one coil to actuate the punch, and means connected with said other contact and actuated by said otherarm 5 References Cited in the file of this Patent for closing said other contact and thereby fully energizing said other coil after said one arm has been attracted by UNITED STATES PATENTS 2,757,732 Worden et a1. Aug. 7, 1956 

